There are many medical conditions which require periodic injections of medication. Diabetes, for example, may be controlled by daily, or more frequent, injections of insulin.
Since injection are painful and troublesome, and each injection represents a possibility for infection, the injections are spaced at intervals as far apart as possible, resulting in peak and valley concentrations of the medication in the bloodstream or at the site in the body requiring the medication. This exposes the patient to the possibility of overdose at peak levels and underdose at valley levels.
It has been found in the treatment of certain conditions such as diabetes, more effective treatment results from constant or repeated small doses of medication. An increase in dosage before, during or after meals can help normalize blood glucose levels. This provides improved control of the medical condition and avoids the problems of under and overdone in medication.
Recently, systems have been developed in which a catheter is semi-permanently implanted in a patient, and a liquid medication is supplied to the patient through the catheter from a reservoir. These devices, however, tend to be large and bulky and in some cases require a considerable power source. The devices using conventional syringes are large because of the space needed to operate a linear syringe. Because of their size, many of these devices are designed to be worn on the chest, in a case slung over the user's shoulder, or on a belt around the user's waist.
Accordingly, there is need for a wearable system for effective administration of medication at a reasonable cost. The present invention satisfies that need.